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PRESENT PROBLEMS OF TECHNOLOGY 587 



ment per decade has decreased by a constant which reduces any 

 ratio one twenty-first less than that of its predecessor. 



By projecting this curve forward, subject to this law of decreas- 

 ing percentages, a very close approximation may be obtained for 

 the future, which will serve as a reliable basis for the solution of 

 the many social, industrial, commercial, and financial problems, 

 based on population. 



Thus there results for the present half-century, the following 

 tabular statement : 



PROBABLE INCREASE IN POPULATION OP THE UNITED STATES DURING THE 



PRESENT SEMI-CENTENNIAL 



Date. Rate of Increase. Population. Numerical Increment 



1900 76,295,220 



1910 23.39 94,249,201 17,952,298 



1920 22.28 115,266,772 21,017,571 



1930 21.22 139,703,327 24,436,555 



1940 20.21 167,923,399 28,220,072 



1950 19.25 200,248,653 32,325,254 



Hence it appears that within the lifetime of many of our contem- 

 poraries the population of this great republic may reasonably be 

 expected to increase 2.6 times, or 260 %, which is at the average 

 rate of 52 % each decade, thus showing the effect of compounding 

 of the curve due to the decennial increment. 



Urban Population 



But it is not merely the rapid growth in numbers for which ade- 

 quate provision should be made. The distribution of the popula- 

 tion is quite as important a problem. With the centralization in 

 great communities the engorgement has become not only incon- 

 venient, but at times oppressive and even dangerous. Ferries, 

 trolleys, elevateds and subways, bridges, and tunnels are all taxed 

 to their utmost limits, and the headway of trains is reduced to the 

 danger-point, yet the facilities are wholly inadequate for the morn- 

 ing and evening service between dormitory and shop. 



Moreover the daily tonnage of food required to be furnished to 

 man and beast, and the waste required to be removed from the 

 great manufacturing centres, is enormous, thus greatly increasing 

 the risks to life and health. This excessive concentration also leads 

 up to the overcrowded tenements, sweat-shops, and brothels, with 

 their unwholesome environments and immoral diversions; for all 

 of which the most tangible remedy is dispersion. 



The density of the population should be held within safe limits 

 by strict sanitary legislation, centres of industries should be estab- 



